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Dylan

Electronics Explorer Digital I/O Votlage Level

Question

Hello,

Is there a way to set the voltage level of the digital I/O on the explorer board to 5V? I see the board has a 5V Vcc supply. Is the only possible way to do open-drain?

Thanks,

Dylan

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Hi @Dylan,

I don't know if there is a way to adjust the static IO, but yes you can adjust the digital Vcc supply in the Supplies tool in the WaveForms software to either 3.3V or 5V.

The Pattern Generator allows you to set each pin (or each group of bins if you are using a bus) to Open-Source, Open-Drain, or other output styles. You can look at the additional options by running the WaveForms software in demo mode for the EE Board.

Let me know if you have any questions about this.

Thanks,
JColvin

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Hi @Dylan

On Analog Discovery (1&2) and Electronics Explorer the output of Digital and Trigger IOs is 0/3.3V logic. For protection the IOs have 220 Ohm PTCs and diodes to GND and 3.3V rail.
The input logic threshold is about 1.42V, or 0.58V with dedicated device configuration selectable under WaveForms/Settings/Device Manager, for AD (1&2) 5th and for EE 7th.
When connecting input voltages above 3.3V (like 5V) use series resistor of about 10K otherwise the protection circuit (diode to 3.3V) might sink too much current (10mA) and the high level voltage on the external circuit could drop.
https://reference.digilentinc.com/reference/instrumentation/analog-discovery-2/reference-manual#digital_io

On Digital Discovery the digital IO voltage is adjustable between 1.2V and 3.3V, concurrently the input threshold is adjusted between 0.58V and 1.42V.
The input protection circuit is 5V compatible with dedicated voltage level translator.
https://reference.digilentinc.com/reference/instrumentation/digital-discovery/reference-manual#io_level_translators

Returning to you original question...
On EExplorer the 3.3/5V VCC fixed supply is not related to the digital IO voltage which is 3.3V
With open drain output to 5V connected directly to the digital IO will pull down you signal to 3.3V

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On 2/3/2018 at 1:14 AM, attila said:

Hi @Dylan

On Analog Discovery (1&2) and Electronics Explorer the output of Digital and Trigger IOs is 0/3.3V logic. For protection the IOs have 220 Ohm PTCs and diodes to GND and 3.3V rail.
The input logic threshold is about 1.42V, or 0.58V with dedicated device configuration selectable under WaveForms/Settings/Device Manager, for AD (1&2) 5th and for EE 7th.
When connecting input voltages above 3.3V (like 5V) use series resistor of about 10K otherwise the protection circuit (diode to 3.3V) might sink too much current (10mA) and the high level voltage on the external circuit could drop.
https://reference.digilentinc.com/reference/instrumentation/analog-discovery-2/reference-manual#digital_io

On Digital Discovery the digital IO voltage is adjustable between 1.2V and 3.3V, concurrently the input threshold is adjusted between 0.58V and 1.42V.
The input protection circuit is 5V compatible with dedicated voltage level translator.
https://reference.digilentinc.com/reference/instrumentation/digital-discovery/reference-manual#io_level_translators

Returning to you original question...
On EExplorer the 3.3/5V VCC fixed supply is not related to the digital IO voltage which is 3.3V
With open drain output to 5V connected directly to the digital IO will pull down you signal to 3.3V

@attila

@Dylan

instead of resistors we can use buffers like ISO7221x. so slope will not be affected.

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